As explained in Applicant's co-pending application Ser. No. 08/237,790, filed May 4, 1994, many different types of illuminated footwear are well known in the art. Typical of such illuminated shoe constructions are those identified in U.S. Pat. Nos. 5,149,489; 5,052,131; 5,033,212; 4,848,009; 4,158,922; 4,130,951; 4,128,861; 4,020,572; 3,893,247; 3,800,133; and 3,564,232 to name a few. Such known constructions generally use miniaturized light-emitting diodes or LEDs, miniaturized point lights, or a plurality of bundled light carrying optical fibers which are housed along with appropriate circuitry for energizing the same within the structure of the shoe so as to produce some type of visible illumination from various portions of the shoe. Typically, such illumination includes point light illumination spaced at various locations around the sole portion of the particular shoe being illuminated as illustrated in U.S. Pat. Nos. 5,033,212; 4,158,922; 4,130,951 and 5,149,489. Also, importantly, only U.S. Pat. No. 4,438,482 discloses a portable illuminating device which comprises a U-shaped member adapted to engage the heel portion of a shoe, this device utilizing various types of incandescent illuminating means which can be either mounted on the surface of the housing, or on the end of a wand or extension member. Although all of the known footwear illumination means achieve some type of decorative illumination of various portions of the shoe, be it either constant or flashing illumination, none of the known constructions utilize linear optics to achieve a neon look of outstanding brightness, evenness and flexibility as will be hereinafter explained, and none utilize linear optics as well as other features of the present invention in a portable unit. The present invention utilizes linear optics in order to achieve its desired illumination effect. Linear light forms have been known for many years and have been utilized in many different types of practical lighting applications such as decorative art forms, pool and spa perimeter and underwater lighting, aisle lighting, and other special effects type illumination. True linear light forms are those in which the source of light is contained within the light form itself such as neon lights, fluorescent lights and other types of tube lighting. Although the present invention strives to achieve a neon type glowing light effect, such simulation is achieved through the use of linear optical conduits wherein the source of illumination is external to the particular optical conduit. In essence, the linear optical conduit functions to conduct and transmit therethrough the light generated by the external source. Optical conduits are commonly referred to as "fiber optics" or "optical fibers". Fiber optics encompass three distinctly different types of functions, namely, telecommunications, coherencies and illumination. Telecommunications fiber optics are used in telephone communications to transmit light from a source to a remote point. Coherent functions involve transmission of a visible image along a bundle of flexible fiber optic conduits to a remote point in such a manner that the placement of the fibers relative to each other at the remote point of site reception is exactly that of the placement of the ends of the fibers relative to each other at the source point of the image of the object which is being transmitted. Both telecommunications and coherent fiber optics are considered point lights and emission of light out of the sides of the optical conduits is to be avoided. Many of the known prior art illuminated shoe constructions utilize some type of fiber optics to achieve point lighting. See, for example, U.S. Pat. No. 4,130,951.
In total contrast, the present invention utilizes a linear optical conduit or other radially emitting light transmissive material wherein the primary function of the linear optical conduit is to provide a means of conducting light from a light source linearly along the length of such optical conduit and emitting such light from the sides thereof along its total length, such that light is emitted in a substantially uniform manner from substantially the entire peripheral surface of the linear optical conduit. The present invention is therefore specifically directed to a self-contained portable footwear illumination device which uses a linear optical conduit to produce a side-light effect somewhat similar to that of a neon light along its entire length.